Pneumatic hammer testing machine



Nov. 20, 1945. H v CORDlANO ET AL 2,389,138

PNEUMATIC HAMMER TESTING MACHINE Filed May 11, 1945 2 Sheets-Sheet 1 IN VEN TORI). #0 0 k C ord/no Joseph J? De Pan/o BY Hyman Lacks WLW Nov. 20, 1945. H. v. CORDIANO ET AL 2,389,138

PNEUMATIC HAMMER TESTING MACHINE Filed May 11, 1945 2 Sheets-Sheet 2 Fr 5 Fig. 7

IN V EN TOR. Hugo K Cord/e170 J'asep/l I Depao/o y Hyman L a c ks Patented Nov. 1945 UNITED STATES OFFICE IPNEUMATIOHAMMER TESTING MACHINE Hugo V. Cordiano, Joseph -'J. De Paolo, and

Hyman Lacks, New York, N. Y.

Application May 11, 1945,1-Serial No. 593,176

4 Claims. (c1.- 7 s 11-) (Granted under the act of March-.3, 1883,:as.

amended April 30, 1928; 370 10. 6 -'757) ping hammers through manual operation is of 7 little value.

An object of this invention is to provide a machine for testingpneumatic chipping hammers in which the thickness of cut made by the hammer chisel may be predetermined and kept constant.

Another object of this inventionis to provide a machine for testing pneumatic chipping hammers in-which'the feed pressure acting upon the hammer may be maintained at a constant and pre'determinedvalue.

Still another object of this invention is to provide a machine for testing pneumatic chipping hammers in which the'ang'le of'thehammer and its chisel with respect to the work may be maintained at a constant and predetermined value.

Further objects and advantages of this invention, as well'as its construction, arrangement and operation, will be apparent from the following description and claims in connection with the accompanying drawings, in which,

Figure 1 is a side elevation of the machine of this invention.

Figure 2 is atop plan view of the machine of Figure 1,

Figure 3 is a partial section of the machine of this invention, taken along the line 3-3 of Figure 1,

Figure 4 is a partial section of the machine of this invention, taken along the line 4-4 of Figure 2,

Figure 5 is an enlarged side elevation of the intermediate cutter piece of the machine,

Figure 6 is an enlarged side elevation of the cutter of'the machine, and

Figure 7 is an enlarged bottom plan view of the-cutter of the machine.

LReferring to the drawings-indetail, the frame- Work-o'fthe machine comprises two upright members or channels H, welded-or otherwise rigidly secured to aheavy base plate I 2. Suitably .af fixed to thetops of channels H are .two parallel, spaced-angles or coverplates l3. Rigidly mounted "on'theupper surfaces of cover plates 13 are twoparallel spaced guideways .ortracks l4. Carriage I|5 rests upon tracks I4, and is slidablyengaged with the outer flanges thereof (Figure .4). Yoke I 6; slidably mounted .on. carriage .l,'5,'.is adapte'd'to engage and hold the forward inner surface of the handle of pneumatic hammer l1. Yokelfiis provided with twodrilled holesthrough which extend threaded rods 18, which are .an

chored at their forward en'dsin carriage [5. In

threadedengagement with each of the rods J8 are two nuts f 9, one .on either sideof yoke l-B', by means of which .yoke 'l6.may be adjusted .relativeto .carriage l5 and "locked at any desired point of adjustment. Bolts v20 extend through. sl ots"2l in yoke l6, engaging threaded bolt holes 22 in carriage I5 (Figure 2). Several pair of bolt holes '22 are provided incarriage L5 being so spaced' thatin any position of yoke lfifrelative to "carriage l5, .bolts 20 extending through slots 2| mayengage at least One pair of 1301131110185 22, Bolts 2ll,"through the medium ,of washers .23, clamp -yoke f6 firmlyagainst carriage .l5 .atany selected position, preventin vibration of yoke l6 relative to carriage l5. Flexibleline 24 is the means by which air is delivered to pneumatic hammer I! under pressure.

Extending from and impelled 'by ,pneumatic hammer I1, and extendin-gthrough aguide hole in carriage I5, is a square ended chisel blank 25. Chisel blank 25 .acts upon and impels a raised portion .of 'the intermediate .cutter piece 26 (Figure '5), whichacts upon .and impels cutter 21 (Figures 6 and 7). Intermediate cutter piece 26 and cutter 21 are retained and guided by the inner flanges of tracks I4 (Figure 4).

Brackets '28extend from the upper end of the forward channel H, and support pulley 29, preferably mounted in antifriction bearings. Stud 3ll projec'tsjfrom theforward end of carriage [5. Cable 3!, connected to stud 30 by'clevis 32, rides on'pulley 29 and supports weights '33. Stop '34, of plastic or other suitable material, limits'the travel'of cutter 21 and retains it in tracks l4.

Suitably aflixed to the .web of the forward channel I l ,as by bolting or welding, is a pair of spaced guides 35 (Figure 3). Rear guides 36, parallel to guides 35 and similarly spaced, extend from base-plate [2 to cover plates [3 approximately midway between channels I l and are fixedly secured at both ends. The ends'of elevator bar3-I extend between "guides 35 and rear guides '36,

Handles '38 are provided on elevator bar 31 to facilitate changing its position. Guides 35 and rear guides 36 are provided with multiple equally and correspondingly spaced holes 39, by means of which elevator bar 31 may be supported in alternate horizontal positions. Elevator bar 31 is fixed at any alternate horizontal position desired by through bolts 40, each of which extends through a pair of corresponding holes 39 provided in guides 35 and rear guides 36 and through a hole provided in elevator bar 31 near its end for that purpose. As illustrated, elevator bar 31 is provided with two holes near each end, adapted to receive through bolts 40.

Slab or plate 4|, the material being worked upon by pneumatic hammer I1 and cutter 21, rests upon elevator bar 31. Looking bolts 42, in threaded engagement with holes 39, may be provided to prevent sidewise movement of slab 4|. Locking bolts 42 may be ordinary machine bolts provided with lock nuts, or may be set screws, wing nuts or any equivalent device, and may bear directly upon slab 4|, or upon side plates (not shown) adapted to be inserted to bear on slab 4|. Plates 43 may be rigidly affixed to the rear surfaces of rear guides 36, and locking bolts 44, similar to locking bolts 42, may be provided in threaded engagement therewith to hold slab 4| firmly against the web of the forward channel I I.

In operation of the invention, slab 4| is lowered into the machine between tracks I4, so that it rests upon elevator bar 31. By means of handles 38, through bolts 40 and holes 39, slab 4| and elevator bar 31 are adjusted vertically to approximately the position desired. Slab 4| is then adjusted vertically until its upper surface is substantially coplanar with the lower surfaces of tracks I4, by means of shims inserted between elevator bar 31 and slab 4|. With slab 4| in the desired position, it may be secured in that position by locking bolts 42 and locking bolts 44. Cutter 21 is then inserted between tracks I4, its cutting edge being brought up to the rear end of the top surface of slab 4|, and the intermediate cutter piece 26 is inserted behind it. A pneumatic hammer I1 to be tested is rigidly fixed in carriage I5 by means of yoke I6, threaded rods I8 and bolts I9, and the assembled carriage I5, pneumatic hammer I1 and chisel blank 25 are engaged with tracks I 4 and slid into place behind intermediate cutter piece 26.

A constant feed pressure for pneumatic hammer I1 is supplied by weights 33, which are attached to cable 3| and act on carriage I5 and pneumatic hammer I1 through clevis 32 nd stud 30. Weights 33 must be large enough to obviate recoil of pneumatic hammer I1, 100 pounds being suitable for the usual size chipping hammer. A supply of compressed air is conducted to pneumatic hammer I1 through flexible line 24. Pneumatic hammer I1 is then permitted to operate for a measured period of time, at the end of which period the chip produced is removed and weighed. The pressure of the air operating pneumatic hammer I1 is maintained constant throughout the period of the test, either manually or by suitable regulating means. The air consumption is measured by a direct reading air meter, a liquid displacement meter, or by any other suitable means. The data thus obtained, the weight of steel chipped per minute and the weight of steel chipped per unit of 'air consumed, are highly indicative of the performance and efficiency of any pneumatic hammer being'tested.

Clevis 32 is provided so that the chip being removed from slab 4| will not interfere with cable 3 I, thereby altering the feed pressure on carriage I5. Clevis 32 also permits chips to be removed and gathered in one piece, simplifying weighing and tagging. Stud 30 is so located that cable 3| pulls in a line which passes approximately through the center of gravity of the loaded carriage I5. The intermediate cutter piece 26 is so shaped that the center axis of the chisel blank 25 passes through the center of gravity of the intermediate cutter piece 26. Cutter 21 is separate from the intermediate cutter piece 26, so that resharpening of cutter 21 does not change the center of gravity of the intermediate cutter piece 26. The shape of the intermediate cutter piece 26 and the use of a separate cutter 21 eliminate any tendency of the cutting edge to dig in -'or run up, since a horizontal component of force only is transmitted to the cutter 21.

The accuracy and value of comparative results obtained by testing in the machine of this invention may be increased by keeping constant other factors than those already pointed out. The angle of pneumatic hammer I1 relative to slab 4|, it will be apparent, is fixed and constantly maintained by the shape of carriage I5. The angle of the cutting edge of cutter 21 relative to slab 4| should be maintained within close limits by frequent honing and grinding. All test plates or slabs 4| should preferably be of the same size, specifications and hardness, and it has been found desirable to do all chipping in the direction of rolling. It has also been found that new, unused hammers cut progressively faster when initially tested. It is desirable, therefore, to run in new hammers by impacting against a steel block for a suitable period of time before testing in the machine of this invention.

It is to be understood that various modifications and changes may be made in this invention without departing from the spirit and scope thereof as set forth in the appended claims.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

1. A machine for testing pneumatic hammers comprising a guideway, means adapted to hold a test plate in fixed relationship with said guideway, means slidably retained by said guideway for holding a pneumatic hammer in fixed angular relationship with said guideway, means for applying a constant feed pressure to said pneumatic hammer holding means, and cutting means slidably retained by said guideway and adapted to receive impact forces at an angle not parallel to said guideway and to transmit said forces in a direction parallel to said guideway.

2. A machine for testing pneumatic hammers comprising a framework and a guideway thereon, means secured to said framework adapted to hold a test plate in fixed relationship with said guideway, means slidably retained by said guideway for holding a pneumatic hammer in fixed angular relationship with said guideway, means for applying a constant feed pressure to said pneumatic hammer holding means, means slidably retained by said guideway and adapted to receive impact forces'at an angle not parallel to said guideway and to transmit said forces in a direction parallel to said guideway, and cutting means slidably retained by said guideway and adapted to be driven 7 by said impact transmitting means.

said forces in a direction parallel to said guideways, and a cutter slidab-ly retained by said guideways adapted to be driven by said impact transmitting means.

4. A machine for testing pneumatic hammers comprising a framework and a pair of spaced guideways thereon, means secured to said framework adapted to hold a test plate in fixed relationship with said guideways, a carriage slidably retained by said guideways for holding a pneumatic hammer in fixed angular relationship with said guideways, means for applying a constant feed pressure to said pneumatic hammer holding means, said pressure applying means acting through the center of gravity of said carriage when carrying a pneumatic hammer and in a direction parallel to said guideways, an intermediate cutter piece retained by said guideways and adapted to receive impact forces from the pneumatic hammer held :by said carriage and to transmit said forces in a direction parallel to said guideways, and a cutter slidably retained by said guideways and adapted to be driven by said intermediate cutter piece.

HUGO V. CORDIANO. JOSEPH J. DE PAOLO. HYMAN LACKS. 

